Genetic Engineering

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  • Created by: Megan
  • Created on: 07-03-14 13:08

Why

Improving a feature of the recipient organism: - inheriting a gene into crop plants to give the plant resistance to herbicides allows farmers to use herbicides as the crops are groing and so increase crop yield. - Inserting a growth-controlling gene, such as the myostatin gene, into livestock promotes muscles growth

Engineering Organisms that can Synthesis useful products:- Inserting the gene for a human hormone into bacteria and growing the bacteria produces large quantities of that hormone for human use. - Inserting the gene for a pharmaceutical chemical into female sheep so that the chemical is produced in their milk means the chemical can be easily collected. - Inserting genes fro beta-carotene production into rice so that the molecule is present in the grain.

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Bacterial Conjugation

...where gentic material may be exchanged

  • Copies of plasmid DNA are passed between bacteria, soemtimes even of different species
  • Plasmids often carry genes associated with antibiotic resistances so the swapping of plasmids is of concern because it speeds up the spread of antibiotic resistace between bacterial populations - resistant strains of bacteria (MRSA) are causing healthcare problmes because the bacterium is commonly found on human skin. The transfer of this bacterium to a wound can lead to a very serious infection.
  • The advantage of bacterial conjugation is that it may contribute to genetic variation and, in the case of antibiotic resistance genes, survival in the presence of the chemicals

Process

  • 1) Conjugation tube forms between a donor and recipient and an enzyme makes a nick in the plasmid
  • 2) Plasmid DNA replication starts. The free DNA strand starts moving through the tube
  • 3) In the recipient cell, replication starts on the transferred DNA
  • 4) The cells move apart and the plasmid in each forms a circle 
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Bacterial Transformation and Pneumonia in Mice

caused by bacterium pneumococcus -> S-strain kills an infection, R-strain does not

When a mix of dead s-strain and live r-strain where injected into mice, the mouse died. It was found that the R-strain had undergone bacterial conjugation with the s-strain so it took on these characteristics and was able to then produce the necessary proteins to kill the mice

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